Heat exchanger

ABSTRACT

Provided is a heat exchanger. The heat exchanger includes a plurality of refrigerant tubes through which a refrigerant flows, a header including a tube connection part coupled to the plurality of refrigerant tubes and a refrigerant inflow part, a first pipe provided in the header to define a first flow space for the refrigerant, a second pipe surrounding the outside of the first pipe to define a second flow space for the refrigerant, and a communication hole defined in the first or second pipe to allow the refrigerant to pass therethrough.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. 119 and 35 U.S.C. 365 to Korean Patent Application No. 10-2013-0031408 (filed on Mar. 25, 2013), which is hereby incorporated by reference in its entirety.

BACKGROUND

The present disclosure relates to a heat exchanger.

A heat exchanger constitutes a refrigeration cycle to allow a refrigerant to flow therein. Also, the heat exchanger cools or heats air through heat-exchange with the air. The heat exchanger may be used for air-conditioners and refrigerators. Here, the heat exchanger may function as a condenser or evaporator according to whether the refrigerant is condensed or evaporated by the heat exchanger.

The heat exchanger is classified into a fin-and-tube type heat exchanger and a micro-channel type heat exchanger according to its shape. The fin-and-tube type heat exchanger includes a plurality of fins and a tube passing through the fins and having a circular shape or a shape similar to the circular shape. The micro-channel type heat exchanger includes a plurality of flat tubes through which a refrigerant flows and a fin disposed between the plurality of flat tubes.

Also, the fin-and-tube type heat exchanger and the micro-channel type heat exchanger exchange heat between an external fluid and a refrigerant flowing into the tube or flat tube. Here, the fins may increase a heat exchange area between the external fluid and the refrigerant flowing into the tube or the flat tube.

Among these, the micro-channel type heat exchanger has been filed and registered by this applicant (KR 10-0547320).

According to Korean Patent Registration No. 10-0547320, the micro-channel type heat exchanger according to the related art may include headers 1 and 2 coupled to a plurality of refrigerant tubes 3. The headers 1 and 2 may be provided in plurality. The first header 1 of the plurality of headers 1 and 2 is coupled to one sides of the plurality of refrigerant tubes 3, and the second header 2 is coupled to the other sides of the plurality of refrigerant tubes 3. Also, a radiation fin 6 for easily heat-exchanging the refrigerant with the external air is disposed between the plurality of refrigerant tubes 3.

The first or second header 1 or 2 has a hollow shape having an empty space therein to provide a flow space through which the refrigerant flows. The refrigerant flowing into the first or second header 1 or 2 may be divided into the plurality of refrigerant tube 3.

However, in the heat exchanger according to the related art, while the refrigerant is divided into the plurality of refrigerant tubes, a relatively large amount of refrigerant is introduced into the refrigerant tube that is closest to a flow direction of the refrigerant, and a relatively small amount of refrigerant is introduced into the refrigerant tube that is the farrest to the flow direction of the refrigerant.

That is, the refrigerant introduced into the heat exchanger is not uniformly distributed into the plurality of refrigerant tubes. In this case, a heat-exchange amount or heat-exchange efficiency may be different according to the positions of the refrigerant tubes to deteriorate the overall performance of the heat exchanger.

SUMMARY

Embodiments provide a heat exchanger having improved heat-exchange efficiency.

In one embodiment, a heat exchanger includes: a plurality of refrigerant tubes through which a refrigerant flows; a header including a tube connection part coupled to the plurality of refrigerant tubes and a refrigerant inflow part; a first pipe provided in the header to define a first flow space for the refrigerant; a second pipe surrounding the outside of the first pipe to define a second flow space for the refrigerant; and a communication hole defined in the first or second pipe to allow the refrigerant to pass therethrough.

The communication hole may include a first communication hole defined in the first pipe to transfer the refrigerant within the first flow space into the second flow space.

The first communication hole may be spaced apart from the first pipe in a longitudinal direction and be provided in plurality.

The communication hole may include a second communication hole defined in the second pipe to transfer the refrigerant within the second flow space into an inner space of the header.

The first and second communication holes may be defined in directions opposite to each other with respect to a center of the first or second pipe.

A first virtual line extending from a center of the first or second pipe to the first communication hole may extend in a direction opposite to that of a second virtual line extending from the center of the first or second pipe to the second communication hole.

The first virtual line may extend in a direction that is close to the refrigerant tube, and the second virtual line may extend in a direction that is away from the refrigerant tube.

A third virtual line extending from the center of the first or second pipe to the refrigerant tube may cross the first or second virtual line.

The third virtual line may perpendicularly cross the first or second virtual line.

The header may include a horizontal type header extending in a horizontal direction, and the first and second communication holes may be defined in the same virtual vertical line.

A distance between the first communication hole and an end of the first pipe may be the same as that between the second communication hole and an end of the second pipe.

The header may includes a horizontal type header extending in a horizontal direction, and the first and second communication holes may be defined in virtual vertical lines different from each other.

A pipe connection part extending from the refrigerant inflow part and coupled to an end of the first pipe may be provided in the header.

At least one portion of the pipe connection part may be rounded.

In another embodiment, a heat exchanger includes: a plurality of refrigerant tubes through which a refrigerant flows; a header to which the plurality of refrigerant tubes are coupled, the header defining a flow space for the refrigerant; a first pipe provided in the header to define a first passage for the refrigerant, the first pipe having a first communication hole through which the refrigerant passes; and a second pipe accommodating the first pipe to define a second passage for the refrigerant, the second pipe having a second communication hole through which the refrigerant passes, wherein a flow direction of the refrigerant discharged through the first communication hole and a flow direction of the refrigerant discharged through the second communication hole are different from each other with respect to the refrigerant tube.

The first and second communication holes may be defined so that the flow directions of the refrigerant discharged through the first and second communication holes are opposite to each other.

The flow direction of the refrigerant discharged through the first communication hole may be close to the refrigerant tube, and the flow direction of the refrigerant discharged through the second communication hole may be away from the refrigerant tube.

The communication hole may be defined so that the refrigerant discharged through the first communication hole is divided to flow into the second passage.

The second communication hole may be defined so that the refrigerant discharged through the second communication hole is divided to flow into a flow space of the header.

The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features will be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a heat exchanger according to a first embodiment.

FIG. 2 is a side cross-sectional view of the heat exchanger according to the first embodiment.

FIG. 3 is a front view illustrating main parts of first and second headers of the heat exchanger according to the first embodiment.

FIG. 4 is a cross-sectional view taken along line I-I′ of FIG. 1.

FIG. 5 is a cross-sectional view of constitutions in the header according to the first embodiment.

FIG. 6 is a cross-sectional view of the constitutions and a refrigerant flow in the header according to the first embodiment.

FIG. 7 is a view of a refrigerant flow in the heat exchanger according to the first embodiment.

FIG. 8 is a cross-sectional view illustrating constitutions and refrigerant flow in a header according to a second embodiment.

FIG. 9 is a cross-sectional view of constitutions in a header according to a third embodiment.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Hereinafter, exemplary embodiments will be described with reference to the accompanying drawings. The invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather, that alternate embodiments included in other retrogressive inventions or falling within the spirit and scope of the present disclosure will fully convey the concept of the invention to those skilled in the art.

FIG. 1 is a perspective view of a heat exchanger according to a first embodiment, FIG. 2 is a side cross-sectional view of the heat exchanger according to the first embodiment, FIG. 3 is a front view illustrating main parts of first and second headers of the heat exchanger according to the first embodiment, and FIG. 4 is a cross-sectional view taken along line I-I′ of FIG. 1.

Referring to FIGS. 1 to 4, a heat exchanger 10 according to a first embodiment includes headers 120 and 130 each of which extends by a predetermined length in a horizontal direction, a plurality of flat tubes 110 that are refrigerant tubes coupled to the headers 120 and 130 to extend in a vertical direction, and a plurality of radiation fins (not shown) arranged at a predetermined distance between the headers 120 and 130 and through which the flat tubes 110 pass.

The headers 120 and 130 may be called “horizontal type headers” in that the headers 120 and 130 extend in a horizontal direction. However, the present disclosure is not limited to the extension direction of the headers. For example, the flat tubes 110 may extend in the horizontal direction.

In detail, the headers 120 and 130 include a first header 120 coupled to one end of each of the flat tubes 110 and a second header 130 coupled to the other end of each of the flat tubes 110. The first and second headers 120 and 130 guide a flow of a refrigerant to switch a flow direction of the refrigerant.

That is, a flow space for the refrigerant is defined in each of the first and second headers 120 and 130. The refrigerant within the first or second header 120 or 130 may be introduced into the flat tubes 110, and the refrigerant flowing in the flat tubes 110 may be switched in direction by the first or second header 120 or 130.

For example, the refrigerant within the first header 120 may be switched in direction and then introduced into the flat tubes 110. The refrigerant flows downward through the flat tubes 110 may be switched in direction within the second header 130 to flow upward.

The first header 120 includes a refrigerant inflow part 122 for introducing the refrigerant into the heat exchanger 10 and a refrigerant discharge part 125 for discharging the refrigerant heat-exchanged within the heat exchanger 10.

Also, the first header 120 includes a first front portion 120 a in which the refrigerant inflow part 122 is disposed, a first rear portion 120 b in which the refrigerant discharge part 125 is disposed, and a partition part 120 c for partitioning the first front portion 120 a from the first rear portion 120 b.

The first front portion 120 a and the first rear portion 120 b are coupled to each other by the partition part 120 c. Also, the refrigerant of the first front portion 120 a may directly flow into the first rear portion 120 b, or the direct flow of the refrigerant of the first rear portion 120 b into the first front portion 120 a may be restricted.

The refrigerant inflow part 122 and the refrigerant discharge part 125 are disposed adjacent to a bottom surface of the first header 120. Thus, the refrigerant may flow upward through the first front portion 120 a of the refrigerant inflow part 122 and then be introduced into the first header 120. Also, the refrigerant may flow downward through the refrigerant discharge part 125 from the first rear portion 120 b of the first header 120.

The second header 130 includes a second front portion 130 a corresponding to the first front portion 120 a, a second rear portion 130 b corresponding to the first rear portion 120 b, and a through hole 135 allowing the second front portion 130 a to communicate with the second rear portion 130 b.

The second front portion 130 a and the second rear portion 130 b are coupled to each other, and the through hole 135 is defined in the coupled portion between the second front portion 130 a and the second rear portion 130 b. The refrigerant of the second front portion 130 a may flow into the second rear portion 130 b through the through hole 135.

The flat tubes 110 may be provided in plurality between the first header 120 and the second header 130. The plurality of flat tubes 110 are spaced apart from each other in a horizontal direction.

A plurality of first tube connection part 121 coupled to one ends of the plurality of flat tubes 110 are disposed on the first header 120. Also, a plurality of second tube connection part 131 to which the other ends of the plurality of flat tubes 110 are coupled are disposed on the second header 130.

The flat tubes 110 are arranged in two rows in front and rear directions.

In detail, as shown in FIG. 2, when viewed from a side surface of the heat exchanger 10, the flat tubes 110 include a first tube 110 a and a second tube 110 b disposed on a side of the first tube 110 a. The first and second tubes 110 a and 110 b may be provided in plurality and thus be respectively coupled to the first and second headers 120 and 130.

The first tube 110 a may be coupled to the first front portion 120 a and the second front portion 130 a, and the second tube 110 b may be coupled to the first rear portion 120 b and the second rear portion 130 b.

While the refrigerant flows into the flat tubes 110, the heat-exchange of the refrigerant may be performed two times. That is, the refrigerant may be heat-exchanged once while flowing from the first front portion 120 a to the second front portion 130 a through the first tube 110 a, and also, the refrigerant may be heat-exchanged once while flowing from the second rear portion 130 b to the first rear portion 120 b through the second tube 110 b.

A plurality of pipes 210 and 250 for guiding a flow of the refrigerant are disposed in the front portion 120 a of the first header 120. The flow space within the first front portion 120 a may form a plurality of passages or flow layers by the plurality of pipes 210 and 250.

In detail, the plurality of pipes 210 and 250 include a first pipe 210 disposed in an inner space of the first front portion 120 a. The first pipe 210 may lengthily extend in the extension direction of the first front portion 120 a and have a hollow cylindrical shape. Also, an inner space of the first pipe 210 is defined as a first flow space for the refrigerant.

The plurality of pipes 210 and 250 include a second pipe 250 surrounding the outside of the first pipe 210. The second pipe 250 may lengthily extend in the extension direction of the first pipe 210 and have a hollow cylindrical shape. Also, an inner space of the second pipe 250 is defined as a second flow space for the refrigerant.

In detail, the second pipe 250 has a diameter D2 greater than that D1 of the first pipe 210. Also, a space in which the refrigerant flows, i.e., the second flow space may be defined between an outer circumferential surface of the first pipe 250 and an inner circumferential surface of the second pipe 210.

Also, the first and second pips 210 and 250 may have substantially the same center. Also, a ratio of an inner sectional area of the second pipe 250 to an inner sectional area of the first front portion 120 a may be about 10:1 to about 2:1

A first communication hole 215 through which the refrigerant flows is defined in the first pipe 210. The first communication hole 215 may be provided in plurality, and the plurality of first communication holes 215 are spaced apart from each other in a longitudinal direction of the first pipe 210.

The refrigerant flowing into the first pipe 210 may flow out of the first pipe 210 through the first communication hole 215. Also, the refrigerant discharged from the first pipe 210 may flow along the inner space of the second pipe 250.

The first commendation hole 215 may be defined in one point of a circumference of the first pipe 210 facing the first tube 110 a. That is, a virtual line extending from an inner center of the first pipe 210 to the first communication hole 215 may extend in a direction that is close to the first tube 110 a or may pass through the inside of the first tube 110 a.

A second communication hole 25 through which the refrigerant flows is defined in the second pipe 250. The second communication hole 255 may be provided in plurality, and the plurality of second communication holes 255 are spaced apart from each other in a longitudinal direction of the second pipe 250.

The refrigerant flowing into the second pipe 250 may flow out of the second pipe 250 through the second communication hole 255. Also, the refrigerant discharged from the second pipe 250 may flow along the inner space of the first front portion 120 a.

The second communication hole 255 may be defined in one point of a circumference of the second pipe 250 in a direction opposite to the direction facing the first tube 110 a. That is, a virtual line extending from an inner center of the second pipe 250 to the second communication hole 255 may extend in a direction away from the first tube 110 a.

The first and second communication holes 215 and 255 may be defined in directions opposite to each other or facing each other with respect to a center of the first or second pipe 210 or 250. On the other hand, the first and second communication holes 215 and 255 may have a phase difference of about 180 degrees with respect to the cylindrical pipes 210 and 250.

Also, a first virtual line extending from the center of the first or second pipe 201 or 250 to the first communication hole 215 and a second virtual line extending from the center of the first or second pipe 210 or 250 to the second communication hole 255 may be parallel to each other and extend in direction opposite to each other.

In another aspect, angles θ1 and θ2 between the center of the first or second pipe and the two virtual lines connecting both ends of the flat tube 110 to each other may range of about 75° to about 90°. Also, the first and second communication holes 215 and 255 may be defined in a circumference of the first or second pipe 210 or 250 to correspond to the angles θ1 and θ2.

As described above, since the first and second communication holes 215 and 255 are different in position or direction, the flow passage of the refrigerant passing through the first and second communication holes 215 and 255 may be elongated and bent several times.

A pipe connection part 205 connected to the refrigerant inflow part 122 is provided in the first front portion 120 a. The pipe connection part 205 extends from the refrigerant inflow part 122 and then is connected to an end of the first pipe 210. To connect the refrigerant inflow part 122 to the first pipe 210, at least one portion of the pipe connection part 205 may be rounded.

A predetermined refrigerant pipe 20 is connected to the refrigerant inflow part 122 at an inlet part of the heat exchanger 10. The refrigerant flowing into the refrigerant pipe 20 is introduced into the first pipe 210 via the refrigerant inflow part 122 and the pipe connection part 205.

As shown in FIG. 4, the first and second communication holes 215 and 255 may have the same virtual vertical line that pass therethrough. That is, a distance between each of the plurality of first communication holes 215 and an end of the first pipe 210 may be the same as that between each of the plurality of second communication holes 255 and an end of the second pipe 250.

FIG. 5 is a cross-sectional view of constitutions in the header according to the first embodiment, FIG. 6 is a cross-sectional view of the constitutions and a refrigerant flow in the header according to the first embodiment, and FIG. 7 is a view of a refrigerant flow in the heat exchanger according to the first embodiment.

Referring to FIGS. 5 to 7, a plurality of refrigerant passages 271, 272, and 273 divided by the plurality of pipes 210 and 250 may be defined in the inner space of the first header 120 of the heat exchanger according to the first embodiment.

In detail, the second pipe 250 is disposed inside the first front portion 120 a, and the first pipe 210 is accommodated into the second pipe 250.

The inner space of the first pipe 210 may define a first passage 271 through which the refrigerant introduced into the first front portion 120 a from the refrigerant inflow part 122 flows. Also, a portion of the inner space of the second pipe 250 except for the first passage 271 is defined as a second passage 272, and an outer space of the second pipe 250 of the inner space of the first front portion 120 a is defined as a third passage 273.

The first passage 271, the second passage 272, and the third passage 273 may communicate with each other by the first and second communication holes 215 and 255.

Also, the second passage 272 may surround the first passage 271, and the third passage 273 may surround the second passage 272.

Since the second passage 272 is formed from an outer circumferential surface of the first pipe 210 to an inner circumferential surface of the second pipe 250, the second passage 272 may form a relatively small passage. Thus, the refrigerant discharged through the first communication hole 215 of the first pipe 210 may be mixed in the second passage 272.

That is, the refrigerant discharged from the first pipe 210 may be a refrigerant before being heat-exchanged. Particularly, the heat exchanger serves as the evaporator, the refrigerant may have a two-phase state (a mixed state of a liquid phase and a gaseous phase). In this case, since the refrigerant flows through the second passage 272, the liquid refrigerant and the gaseous refrigerant may be uniformly mixed with each other, and then, the mixed refrigerant may be divided into the flat tubes 110.

Referring to FIG. 6, a flow of the refrigerant in the first front portion will be simply described.

The refrigerant introduced into the first header 120 through the refrigerant inflow part 122 may flow into the first passage 271 of the first pipe 210. Here, the refrigerant may flow from one end of the first header 120 to the other end in a horizontal direction (a direction from a right side to a left side in FIG. 1).

While the refrigerant flows into the first passage 271, at least one portion of the refrigerant may be discharged to the outside of the first pipe 210 through the plurality of first communication holes 215. Here, a direction in which the refrigerant is discharged through the first communication hole 215 may be a direction facing the flat tubes 110.

If the refrigerant is discharged from the first communication hole 215, the refrigerant flows into the second passage 272 of the second pipe 250. In this process, the refrigerant is divided into both sides of the first communication hole 215 to flow in a backward direction, i.e., a direction away from the flat tubes 110.

Also, the divided refrigerant may be combined and then discharged into the third passage 273 through the plurality of second communication holes 255. Here, the refrigerant may flow in the direction away from the flat tubes 110.

The refrigerant discharged from the second communication holes 255 may be divided into both sides to flow in a forward direction, i.e., a direction facing the flat tubes 110. Also, the refrigerant of the third passage is introduced into the flat tubes 110.

As described above, the refrigerant of the first tube 210 may be divided and bent several times until the refrigerant is introduced into the flat tubes 110. Thus, a flow path of the refrigerant may be elongated in length. Thus, a phenomenon in which the refrigerant is concentrated into the flat tube 110 that is the closest to the refrigerant inflow part 122 may be prevented, and thus, the refrigerant may uniformly flow in a longitudinal direction by an inertial force.

Referring to FIG. 7, a flow of the refrigerant in the heat exchanger 10 will be simply described.

The refrigerant introduced into the first front portion 120 a of the first header 120 through the refrigerant inflow part 122 flows into the first pipe 120. As illustrated in FIG. 6, the refrigerant passing through the plurality of passages 271, 272, and 273 is introduced into the first tube 110 a through the first tube connection part 121.

The refrigerant passing through the first tube 110 a is introduced into the second front portion 130 a of the second header 130 through the second tube connection part 131, and also, is introduced into the second rear portion 130 b via the through hole 135. Also, the refrigerant is introduced into the first rear portion 120 b after passing through the second tube 110 b and then is discharged into the heat exchanger 10 through the refrigerant discharge part 125.

As described above, the refrigerant performs the heat-exchange two times while circulating the first and second headers 120 and 130 and thus is condensed (in the case where the heat exchanger is the condenser) or evaporated (in the case where the heat exchanger is the evaporator).

Hereinafter, descriptions will be made according to second and third embodiments. Since the second third embodiments are the same as the first embodiment except for only a portion of the constitutions, different points between the first embodiment and the second and third embodiments will be described principally, and descriptions of the same parts will be denoted by the same reference numerals and descriptions of the first embodiment.

FIG. 8 is a cross-sectional view illustrating constitutions and refrigerant flow in a header according to a second embodiment.

Referring to FIG. 8, a plurality of pipes 310 and 315 are provided in a first front portion 120 a of a first header 120 according to the second embodiment.

The plurality of pipes 310 and 315 include a first pipe 310 having a first communication hole 315 and a second pipe 350 surrounding the outside of the first pipe 310 and having a second communication hole 355. The first and second pipes 310 and 350 may have substantially the same center.

The first and second pipes 310 and 350 according to the current embodiment may be disposed similar to the first and second pipes 210 and 250 according to the first embodiment. However, the current embodiment is different from the first embodiment in that the first and second communication holes 315 and 355 are different in position.

The first and second communication holes 315 and 355 are disposed to face a side direction in FIG. 8.

In detail, a first virtual line extending from a center of the first or second pipe 310 or 350 toward the first communication hole 315 and a third virtual line extending from the center of the first or second pipe 310 or 350 toward a flat tube 110 may cross each other. For example, the first virtual line and the third virtual line may be perpendicular to each other.

Also, a second virtual line extending from the center of the first or second pipe 310 or 350 toward the second communication hole 355 and the third virtual line extending from the center of the first or second pipe 310 or 350 toward the flat tube 110 may cross each other. For example, the second virtual line and the third virtual line may be perpendicular to each other.

According to the above-described constitutions, the refrigerant flowing into the first pipe 310 is discharged to a side of the flat tube 110 through the first communication hole 315, and the discharged refrigerant is divided into both sides to flow an opposite side of the flat tube 110 (see FIG. 8).

Also, the refrigerant flowing into the second pipe 350 is combined and then discharged through the second communication hole 355 to flow into the flat tube 110 in the first front portion 120 a.

Here, the refrigerant is divided into both sides in the second communication hole 355 to flow to the flat tube 110. However, in the divided refrigerant, an amount of refrigerant divided along a path that is defined close to the flat tube 110 in the second communication hole 355 may be relatively large.

According to the current embodiment, the passage may be bent several times by passing through a first passage defined in the first pipe, a second passage defined in the second pipe, and a third passage defined in the first front portion 120 a. Thus, a flow path of the refrigerant may be elongated in length.

FIG. 9 is a cross-sectional view of constitutions in a header according to a third embodiment.

Referring to FIG. 9, a first communication hole 215 defined in a first pipe 210 and a second communication hole 255 defined in a second pipe 250 according to a third embodiment may be disposed along virtual vertical lines different from each other, respectively.

That is, a distance between each of the plurality of first communication holes 215 and an end of the first pipe 210 may be different from that between each of the plurality of second communication holes 255 and an end of the second pipe 250.

That is to say, the first communication holes 215 and the second communication holes 255 may be alternately defined with respect to a horizontal direction in which the first header 120 extends.

According to the above-described constitutions, an inertial force that is applied horizontally from the refrigerant inflow part 122 and a flow force that is applied vertically to the flat tube 110 may act on the refrigerant.

Thus, in a state where the refrigerant discharged into the first pipe 210 through the plurality of first communication holes 215 further flows in a horizontal direction, the refrigerant may be easily discharged from the second pipe 250 through the second communication hole 255 adjacent to the first communication hole 215. Therefore, the refrigerant may be effectively distributed into the plurality of flat tubes 110.

According to the proposed embodiments, since the plurality of tubes are provided in the header, and the communication holes through which the refrigerant flows are defined in the plurality of tubes, the refrigerant may uniformly flow over the whole length of the header. Thus, the refrigerant may be uniformly distributed into the refrigerant tubes connected to the header.

Particularly, since one tube of the plurality of tubes is accommodated in the other tube, and the communications holes are defined in directions different from each other, the flow passage of the refrigerant may be bent several times and elongated.

Thus, a phenomenon in which the refrigerant is concentrated into the front refrigerant tube that is the closest to the refrigerant inflow part of the header in the flow direction of the refrigerant may be prevented. Therefore, the refrigerant may be uniformly distributed into the rear refrigerant tube that is the farrest to the refrigerant inflow part of the header by the inertial force.

In addition, the small space between the one tube and the other tube may act as the passage for the refrigerant to mix the refrigerants. Therefore, the gaseous and liquid refrigerants may be uniformly distributed.

Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art. 

What is claimed is:
 1. A heat exchanger comprising: a plurality of refrigerant tubes through which a refrigerant flows; a header comprising a tube connection part coupled to the plurality of refrigerant tubes and a refrigerant inflow part; a first pipe provided within the header to define a first flow space for the refrigerant; a second pipe surrounding the outside of the first pipe to define a second flow space for the refrigerant; and at least one communication hole defined in the first or second pipe to allow the refrigerant to pass through the first or second pipe.
 2. The heat exchanger according to claim 1, wherein the communication hole comprises a first communication hole defined in the first pipe to pass the refrigerant within the first flow space of the first pipe into the second flow space of the second pipe.
 3. The heat exchanger according to claim 2, wherein the first communication hole are provided in plurality and are spaced apart from each other in a longitudinal direction of the first pipe.
 4. The heat exchanger according to claim 3, wherein the communication hole comprises a second communication hole defined in the second pipe to pass the refrigerant within the second flow space of the second pipe into an inner space of the header.
 5. The heat exchanger according to claim 4, wherein the communication hole are provided in plurality and are spaced apart from each other in a longitudinal direction of the second pipe.
 6. The heat exchanger according to claim 5, wherein the first and second communication holes are defined in directions different from each other with respect to a center of the first or second pipe.
 7. The heat exchanger according to claim 6, wherein a first virtual line extending from a center of the first or second pipe to the first communication hole extends in a direction opposite to a second virtual line extending from the center of the first or second pipe to the second communication hole.
 8. The heat exchanger according to claim 6, wherein a first virtual line extending from a center of the first or second pipe to the first communication hole extends in a direction that is closer to the refrigerant tube than a second virtual line extending from the center of the first or second pipe to the second communication hole.
 9. The heat exchanger according to claim 7, wherein a third virtual line extending from the center of the first or second pipe to the refrigerant tube crosses the first or second virtual line.
 10. The heat exchanger according to claim 9, wherein the third virtual line perpendicularly crosses the first or second virtual line.
 11. The heat exchanger according to claim 5, wherein the header comprises a horizontal type header extending in a horizontal direction, and the first and second communication holes are defined on a same virtual vertical line that is perpendicular to the horizontal direction of the horizontal type header.
 12. The heat exchanger according to claim 11, wherein a distance between the first communication hole and an end of the first pipe is the same distance as that between the corresponding second communication hole and an end of the second pipe.
 13. The heat exchanger according to claim 5, wherein the header comprises a horizontal type header extending in a horizontal direction, and a virtual vertical line that is perpendicular to the horizontal direction of the horizontal type header that passes through the first communication hole does not pass through the second communication hole.
 14. The heat exchanger according to claim 1, wherein a pipe connection part extending from the refrigerant inflow part and coupled to an end of the first pipe is provided within the header.
 15. The heat exchanger according to claim 14, wherein at least a portion of the pipe connection part is rounded.
 16. A heat exchanger comprising: a plurality of refrigerant tubes through which a refrigerant flows; a header to which the plurality of refrigerant tubes are coupled, the header defining a flow space for the refrigerant; a first pipe provided within the header to define a first passage for the refrigerant, the first pipe having a first communication hole through which the refrigerant passes; and a second pipe accommodating the first pipe to define a second passage for the refrigerant, the second pipe having a second communication hole through which the refrigerant passes, wherein a flow direction of the refrigerant discharged through the first communication hole and a flow direction of the refrigerant discharged through the second communication hole are different from each other with respect to the refrigerant tube.
 17. The heat exchanger according to claim 16, wherein the first and second communication holes are defined in the respective first and second pipes so that the flow directions of the refrigerant discharged through the first and second communication holes are opposite to each other.
 18. The heat exchanger according to claim 17, wherein the flow direction of the refrigerant discharged through the first communication hole is closer to the refrigerant tube than the flow direction of the refrigerant discharged through the second communication hole.
 19. The heat exchanger according to claim 16, wherein the communication hole is defined in the first pipe with respect to the second pipe so that the refrigerant discharged through the first communication hole divides to flow into the second passage.
 20. The heat exchanger according to claim 16, wherein the second communication hole is defined in the second pipe with respect to the header so that the refrigerant discharged through the second communication hole divides to flow into a flow space of the header. 